I'f you're just starting out the most important way to protect your hands is to remember technique before power, i.e. when you start hitting bags you don't need to pound away on the fuckers as hard as you can, work on correct technique and building speed before power.

Other than that wrap the hands and ask around for glove recommendations.

Some wacky guy with pink hair did a good instructional vid on hand wrapping here:

Wrapping your hands will also help stop your gloves going rancid from sweat.

Find gloves that protect the thumb, your thumb will bang all the time. Learn from your coach how to wrap good, and don't hit hard at first. When you have some time, do pushups on your fists to strengthen the area.